Well sadly my car has been sitting for some time. Still having the slight rough running. Life been happening so the car has been sitting. Last fall my uncle looked at it and he did adjust the timing, still around 10 degree and adjusted the carb mixture screws. That seemed to clean it up a little. I drove it today for an hour, ran decent, still feel a roughness when I get out of the gas on the HWY, like a slight surge back and forth felt in the car when sitting in it, very slight surge. At a stop you can feel it a tiny bit (car shake every so little). So I did what little I know on putting a vac gauge to the car. I connected it to the intake port in front of carb. The gauge ran up and to a steady needle hold to 19/20 reading. When I goosed it hard it went to 0 then back to a little over 20 then settled right back into 19/20 steady, no bouncing needle. From what I have read that holding vac like that means there is a decent chance I don't have an internal motor issue. I also connected to a vac source at the back of the motor and got the 20 reading. Does this test rule out any cyc/rings issues 100%? The vac line from the brake booster is not clamped on to it. That hose is very old and hard. Could it be letting a vac leak happen? The line to the trans, should I climb under the car and check the connection at the trans? Should I do another compression check to double check when I saw last fall?
Yes that is good! Run some seafoam through the carb to clean out the tiny passages that get plugged up.
I did a compression check today. They all read good. A few low ones ( none side by side to another cyc) but still healthy and with in the 10% rule.
It's always a great feeling doing a compression test and finding out you have healthy rings, especially if it's on a car you just forked over money for (I seem to do that a lot ). Good work!
All the plugs were clean, light white ashy look, no soot buildup, not cracks, nothing. So perhaps I have a jacked up valve somewhere. I forgot but will do the pull the plug wire one at a time on the each cyc, see if one does not make it run worse which would clue in that cyc may be the issue.
Another simple test: use a temperature gun and check the exhaust temps. If you get a hot or cold one - there is your issue.
Yes, at the manifold where it comes out of the head, or on the headers if you have them. You are trying to check the relative exhaust temperature of each cylinder. If its hot you have a lean cylinder and if its cold its not burning/firing. Its not terribly accurate like an O2 sensor on each cylinder but it's a quick rough check.
